Process to produce polycarbamate, polycarbamate produced thereby and a coating composition comprising the polycarbamate

ABSTRACT

A process to prepare polycarbamate comprising adding urea to a polyol in the presence of at least one catalyst selected from the group consisting of compounds having the following formula M m Z n ; wherein M is a divalent metal, and Z is an anionic functionality or a functionality capable of forming a covalent bond with M and wherein n times a valence number of Z equals X and m times two equals Y wherein the absolute value of X equals the absolute value of Y is provided. Also provided are a polycarbamate produced according to the process and a coating composition comprising the polycarbamate.

CONTINUITY INFORMATION

This application is an U.S. 371 national stage application of PCTapplication PCT/2014/051176 filed on Aug. 15, 2014, which in turnclaimed priority to U.S. Provisional Application No. 61/866,072, whichwas filed on Aug. 15, 2013, the disclosures of which are incorporatedherein by reference.

FIELD OF INVENTION

The instant invention relates to a process to produce polycarbamate,polycarbamate produced thereby and a coating composition comprisingpolycarbamate.

BACKGROUND OF THE INVENTION

One of the widely used class of catalysts for the reaction of polyolswith amides or esters is tin-based catalysts. However, tin-basedmaterials are now banned in coating materials in some regions such asEurope. Alternative catalysts for the reaction of polyols with amides oresters would therefore be desirable.

SUMMARY OF THE INVENTION

The instant invention is a process to produce polycarbamate,polycarbamate produced thereby and a coating composition comprisingpolycarbamate.

The process according to the present invention comprises adding urea toa polyol in the presence of at least one catalyst selected from thegroup consisting of: (i) compounds having the following formulaM_(m)Z_(n); wherein M is a divalent metal, and Z is an anionicfunctionality or a functionality capable of forming a covalent bond withM and wherein n times a valence number of Z equals X and m times twoequals Y wherein the absolute value of X equals the absolute value of Y.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention is a process to produce polycarbamate,polycarbamate produced thereby and a coating composition comprisingpolycarbamate.

The process according to the present invention comprises adding urea toa polyol in the presence of at least one catalyst selected from thegroup consisting of: (i) compounds having the following formulaM_(m)Z_(n); wherein M is a divalent metal, and Z is an anionicfunctionality or a functionality capable of forming a covalent bond withM and wherein n times a valence number of Z equals X and m times twoequals Y wherein the absolute value of X equals the absolute value of Y.

In an alternative embodiment, the instant invention further provides apolycarbamate produced according to any embodiment of the inventiveprocess disclosed herein.

In another alternative embodiment, the instant invention furtherprovides a coating composition comprising the polycarbamate according toany of the embodiments disclosed herein.

Urea

In embodiments of the process, the urea may be added in either solid orliquid form. In a specific embodiment, the urea is added in liquid form.

The liquid form of the urea (or “liquid urea”) may be achieved in anyacceptable manner. For example, the urea may be dissolved in a firstsolvent. Alternatively, the urea may be melted. In yet anotheralternative, the urea may be suspended in a clathrate. A urea clathratemay also be known as a urea inclusion compound and may have thestructure as described in “Supramolecular Chemistry” John Wiley & Sons,Jonathan w. Steed, Jerry L. Atwood, pp. 393-398 and Harris, K. D. M.,“Fundamental and Applied Aspects of Urea and Thiourea InclusionCompounds”, Supramol. Chem. 2007, 19, 47-53.

The liquid form of the urea may alternatively be present in acombination of liquid forms.

In a particular embodiment, the urea is dissolved in water. In anotherembodiment, the urea may be dissolved in a mixture of two or more firstsolvents. Such first solvents include organic solvents. In analternative embodiment, the urea is dissolved in one or more firstsolvents selected from water and organic alcohols. In one embodiment,urea is partially soluble in the first solvent or mixture of firstsolvents. In yet another embodiment, urea is fully soluble in the firstsolvent or mixture of first solvents.

Polyol

As used herein, the term “polyol” means an organic molecule having atleast 2 —OH functionalities. As used herein, the term “polyester polyol”means a subclass of polyol that is an organic molecule having at least 2alcohol (—OH) groups and at least one carboxylic ester (CO₂—C)functionality. The term “alkyd” means a subclass of polyester polyolthat is a fatty acid-modified polyester polyol wherein at least onecarboxylic ester functionality is preferably derived from anesterification reaction between an alcoholic —OH of the polyol and acarboxyl of a (C₈-C₆₀) fatty acid. The polyol may be any polyol; forexample, the polyol may be selected from the group consisting ofacrylic, styrene-acrylic, styrene-butadiene, saturated polyester,polyalkylene polyols, urethane, alkyd, polyether or polycarbonate. Inone exemplary embodiment, the polyol component comprises hydroxyethylacrylate. In another exemplary embodiment, the polyol componentcomprises hydroxyethyl methacrylate.

The reaction mixture may comprise from 10 to 100 percent by weight ofpolyol; for example, from 30 to 70 percent by weight of polyol. In oneembodiment, the polyol has a functional structure of a 1,2-diol,1,3-diol, or combinations thereof.

The polyol can be non-cyclic, straight or branched; cyclic andnonaromatic; cyclic and aromatic, or a combination thereof. In someembodiments the polyol comprises one or more non-cyclic, straight orbranched polyols. For example, the polyol may consist essentially of oneor more non-cyclic, straight or branched polyols.

In one embodiment, the polyol consists essentially of carbon, hydrogen,and oxygen atoms. In another embodiment, the polyol consists of primaryhydroxyl groups. In yet another embodiment, the hydroxyl groups are inthe 1,2 and/or 1,3 configuration. Exemplary polyol structures are shownbelow for illustrative purposes.

Polyol useful in embodiments of the inventive process include oligomersor polymers derived from hydroxy-containing acrylic monomeric units.Suitable monomers may be, but are not limited to, hydroxyethyl acrylate,hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxydodecyl acrylate,hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutylmethacrylate, hydroxydodecyl methacrylate, hydroxybutyl vinyl ether,diethylene glycol vinyl ether and a combinations thereof. The polyoluseful in embodiments may be prepared by reacting at least onehydroxyl-containing monomer with one or more monomers. Suitable monomersmay be, but are not limited to, vinyl monomers such as styrene, vinylether, such as ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinylether, ester of unsaturated carbonic acid and dicarbonic acid, such asmethyl acrylate, methyl methacrylate, ethyl acrylate, ethylmethacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecylacrylate, dodecyl methacrylate, dimethyl maleate and a mixture thereof.

Polyols useful in certain embodiments of the inventive process includepolyether polyols and polyester polyols. Suitable polyols include, forexample, ethylene glycol, diethylene glycol, neopentyl glycol,1,4-butanediol, 1,6-hexanediol, glycerol, pentaerythritol, sorbitol andmannitol. Suitable glycols thus include ethylene glycol, propyleneglycol, diethylene glycol, triethylene glycol, tetraethylene glycol,pentaethylene glycol, hexaethylene glycol, heptaethylene glycol,octaethylene glycol, nonaethylene glycol, decaethylene glycol, neopentylglycol, glycerol, 1,3-propanediol, 2,4-dimethyl-2-ethyl-hexane-1,3-diol,2,2-dimethyl-1,2-propanediol, 2-ethyl-2-butyl-1,3-propanediol,2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, 2,2,4-tetramethyl-1,6-hexanediol,thiodiethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol,1,4-cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol,2,2,4-tetramethyl-1,3-cyclobutanediol, p-xylenediol, hydroxypivalylhydroxypivalate, 1,10-decanediol, hydrogenated bisphenol A,trimethylolpropane, trimethylolethane, pentaerythritol, erythritol,threitol, dipentaerythritol, sorbitol, mannitol, glycerine,dimethylolpropionic acid, and the like.

Polycarboxylic acids useful in the invention may include, but are notlimited to, phthalic anhydride or acid, maleic anhydride or acid,fumaric acid, isophthalic acid, succinic anhydride or acid, adipic acid,azeleic acid, and sebacic acid, terephthalic acid, tetrachlorophthalicanhydride, tetrahydrophthalic anhydride, dodecanedioic acid, sebacicacid, azelaic acid, 1,4-cyclohexanedicarboxylic acid,1,3-cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid,glutaric acid, trimellitic anhydride or acid, citric acid, pyromelliticdianhydride or acid, trimesic acid, sodium sulfoisophthalic acid, aswell as from anhydrides of such acids, and esters thereof, where theyexist. Optionally monocarboxylic acids may be employed including, butnot limited to, benzoic acid. The reaction mixture for producing alkydsincludes one or more aliphatic or aromatic polycarboxylic acids,esterified polymerization products thereof, and combinations thereof. Asused herein, the term “polycarboxylic acid” includes both polycarboxylicacids and anhydrides thereof. Examples of suitable polycarboxylic acidsfor use in the present invention include phthalic acid, isophthalicacid, terephthalic acid, tetrahydrophthalic acid, naphthalenedicarboxylic acid, and anhydrides and combinations thereof.

Addition Step

The addition of urea to polyol may be accomplished by any means. In aparticular embodiment of the process, the adding the urea to the polyolis conducted in a batch manner. In a particular embodiment of theprocess, the adding the urea to the polyol is conducted in a semi-batchmanner. In one embodiment, the urea is added at a constant rate over aperiod of time in which the reaction proceeds. In yet anotherembodiment, the urea is added to the polyol at more than one rate, withthe rate changing over the time period in which the reaction proceeds.In yet another embodiment, the urea is added to the polyol using apulsed constant rate in which the urea is added at a rate for a firstperiod of time, followed by a second period of no urea addition,followed by urea addition at the same rate for a third period of time,and so on. In another alternative embodiment, the urea in liquid form isadded to the polyol using a pulsed variable rate in which the urea isadded at a first rate for a first period of time, followed by a secondperiod of no urea addition, followed by urea addition at a second ratefor a third period of time, and so on.

In one embodiment of the process, the polyol is complete polyol in theabsence of any solvent. In an alternative embodiment of the process, thepolyol is dissolved in a second solvent prior to the adding the urea tothe dissolved polyol. The second solvent may be any solvent or mixtureof solvents in which the polyol is soluble or partially soluble. Incertain embodiments, the first and second solvents form a heterogeneousazeotrope allowing removal of the first solvent by decantation or othermeans. In certain embodiments, removal of the first solvent from aheterogenous azeotrope permits concurrent removal of certainby-products, such as ammonia, which are soluble in the first solvent. Inyet an alternative embodiment, the first and second solvents form aheterogeneous azeotrope allowing removal of the first solvent andfurther wherein the second solvent is returned to the reactor.

In yet another embodiment, the urea is added to the polyol in a gradientmethod, as described in pending U.S. patent application Ser. No.13/955,612, filed on Jul. 31, 2013, entitled “Process to ProducePolycarbamate Using a Gradient Feed of Urea,” the disclosure of which isincorporated herein by reference in its entirety.

In certain embodiments, the process achieves at least a 50% conversionof hydroxyl groups of the polyol. All individual values and subrangesfrom at least 50% conversion are included herein and disclosed herein;for example, the hydroxyl conversion may range from a lower limit of50%, or in the alternative, the hydroxyl conversion may range from alower limit of 55%, or in the alternative, the hydroxyl conversion mayrange from a lower limit of 60%, or in the alternative, the hydroxylconversion may range from a lower limit of 65%, or in the alternative,the hydroxyl conversion may range from a lower limit of 70%, or in thealternative, the hydroxyl conversion may range from a lower limit of 75%or in the alternative, the hydroxyl conversion may range from a lowerlimit of 80%, or in the alternative, the hydroxyl conversion may rangefrom a lower limit of 85%.

Divalent Metal Catalysts

Catalysts included in embodiments of the inventive process are selectedfrom the group consisting of: (i) compounds having the following formulaM_(m)Z_(n); wherein M is a divalent metal, and Z is an anionicfunctionality or a functionality capable of forming a covalent bond withM and wherein n times a valence number of Z equals X and m times twoequals Y wherein the absolute value of X equals the absolute value of Y.

Exemplary divalent metals include Manganese (II) (“Mn(II)”), Zinc (II)(“Zn(II)”), Calcium (II) (“Ca(II)”), Magnesium (II) (“Mg(II)”), Lead(II) (“Pb”), Cobalt (II) (“Co”) and Barium (II) (“Ba(II)”).

Exemplary Mn(II)-containing catalysts include Mn(II) acetylacetonate,Mn(II) 2-ethylhexanoate, Mn(II) bis(trifluoromethanesulfonate),Manganese carbonate, Mn(ClO₄)₂, Magnesium halides, Magnesium(II)hydroxide and Manganese (II) oxide.

Exemplary Zn(II)-containing catalysts include Zn(II) acetylacetonate,Zn(II) 2-ethylhexanoate, Zn(II) triflate, Zn(II) trifluoro acetatehydrate, Zn(II) 2-mercaptopyridine-N-oxide, Zn(II)Bis(2,2,6,6-tetramethyl-3,5-hetanedionate, Zn(II) toluenesulfonate,Zn(II) dibutyldithiocarbamate, Zn(II) hexafluoroacetylacetonate, zincoxides, zinc halides, zinc hydroxide and zinc halide hydroxide.

Exemplary Ca(II)-containing catalysts include Ca(II) acetylacetonate,Ca(II) 2-ethylhexanoate, Ca(II) bis(trifluoromethanesulfonate), Calciumcarbonate, Calcium stearate, Ca(ClO₄)₂, Calcium halides, Calciumhydroxide, Calcium methoxide, Calcium ethoxide, Calcium isopropoxide andCa(II)oxide.

Exemplary Mg(II)-containing catalysts include Mg(II) acetylacetonate,Mg(II) 2-ethylhexanoate, Mg(II) bis(trifluoromethanesulfonate),Magnesium carbonate, Magnesium stearate, Mg(ClO₄)₂, and Magnesiumhalides, Magnesium hydroxide, Magnesium ethoxide, Magnesium butoxide,Mg(II)oxide.

Exemplary Pb(II)-containing catalysts include Pb(II) acetylacetonate,Pb(II) 2-ethylhexanoate, Pb(II) trifluoromethanesulfonate, Lead(II)hydroxide, Lead(II) halides and Pb(II) oxide.

Exemplary Co(II)-containing catalysts include Co(II) acetylacetonate,Co(II) 2-ethylhexanoate, Co(II) trifluoromethanesulfonate, Cobalt(II)halides, Cobalt(II) hydroxide and Cobalt(II) oxide.

Exemplary Ba(II) catalysts include Ba(II) acetylacetonate, Ba(II)2-ethylhexanoate, Ba(II) bis(trifluoromethanesulfonate), Bariumcarbonate, Ba(ClO₄)₂, Barium hydroxide and Ba(II)oxide.

Z is an anionic functionality or a functionality capable of forming acovalent bond with M. As can be seen from the foregoing examples, Z maybe a combination of one or more anionic functionalities, one or morefunctionalities capable of forming a covalent bond with M, or acombination of anionic functionality(ies) and functionality(ies) capableof forming a covalent bond with M. In those instances where Z is acombination of more than one functionality, for example Z1_(n1)Z2_(n2),one of ordinary skill in the art would understand that the absolutevalue of the sum of the valences times the appropriate n equals theabsolute value of m times two. For example, if the catalyst has theformula M_(m)Z1_(n1)Z2_(n2)=Mg(ClO₄)₂, then M=Mg(II), m=1, Z1=ClO₄ witha valence of −1, Z2=ClO₄ with a valence of −1, n1=1 and n2=1, m times2=Y=2 and n1 time −1=−1 and n2 times −1=−1, and X=−1+−1=−2, andtherefore the absolute values of Y and X are equal.

Exemplary components of the Z groups include 2-ethylhexanoate, benzoate,hexafluoroacetylacetonate, isopropoxide, acetyl acetonate, phenoxide,2-mercaptopyridine-N-oxide, toluenesulfonate, stearate, tert-butoxide,neodecanoate, citrate, trifluoromethane sulfonate, n-butoxide,trifluoroacetate, dibutyldithiocarbamate,1,1,1-trifluoro-2,4-pentanedionate,2,2,6,6,-tetramethyl-3,5-hexanedionate, cresylate, ethoxide, methoxide,triethanolaminato, 2-methyl-2-butoxide, oxo, fluoride, chloride, bromideor iodide as well as other anionic functionalities capable of binding toa trivalent metal, mixtures thereof and chelates thereof.

In one embodiment of the process, the adding the urea to the polyoloccurs in the presence of any one or more of the foregoing catalysts.

Additional Catalysts

In a certain embodiment of the process, the adding the urea to thepolyol occurs in the presence of one or more additional catalystsselected from the group consisting of carbamylation catalysts. Suchsecond carbamylation catalysts include, for example, dibutyltin oxide,dibutyltin acetate, tetravalent metal based compounds and trivalentmetal-based compounds.

By-Products

In an alternative embodiment, the instant invention provides a process,polycarbamate and coatings comprising the polycarbamate, in accordancewith any of the preceding embodiments, except that a 100% solids productof the polycarbamate comprises less than 5 wt % total of biuret,cyanuric acid, and polyallophanate. All individual values and subrangesfrom less than 5 wt % are included herein and disclosed herein; forexample, the total amount of biuret, cyanuric acid, and polyallophanatein a 100 wt % solids polycarbamate product may be from an upper limit of5 wt %, or in the alternative, from an upper limit of 4 wt %, or in thealternative, from an upper limit of 3 wt %, or in the alternative, froman upper limit of 2 wt %, or in the alternative, from an upper limit of1 wt %, or in the alternative, from an upper limit of 0.5 wt %.

Coatings

The polycarbamate according to the embodiments disclosed herein may beused in coating compositions. Such coatings may include, for example,polyurethane from crosslinking reaction of the polycarbamate andcomponents with multiple aldehyde functionalities. Exemplary end usesfor such coatings include metal, ceramic, wood and plastic coatings,including for example wind blade coatings and automotive coatings.

EXAMPLES

The following examples illustrate the present invention but are notintended to limit the scope of the invention.

Inventive Example 1: Semi-Batch Addition of Urea to Polyol in Presenceof Zinc Acetylacetonate

A 1-L reactor with heating mantle was used in the reaction. The reactorwas equipped with an agitator, a thermal-couple and a nitrogen sparger.A water-cooled condenser was connected to the adaptor on the reactorlid. The overhead condensate was collected by a receiver and thenon-condensable went through a bubbler filled with mineral oil and thenentered a 1-L scrubber filled with water.

765.8 g PARALOID AU-608X polyol (commercially available from The DowChemical Company) which consists of 58% solid and 42% solvent (xylenes)was added to the reactor, which had 0.68 mol hydroxyl functionality.4.91 g zinc acetylacetonate (99% pure) was added to the reactor. 41.33 g99% pure urea was used in this reaction. The heating mantle was startedand set at 158° C. The nitrogen sparging flow rate was set at 20 sccm.The reaction mixture was agitated at 100 rpm and then adjusted to 400rpm when the reactor temperature was over 60° C. 30% of Urea was addedto the reactor when the reactor temperature reached 138° C. and thereaction timer was started. The reaction was carried out between138-142° C. Solid urea was added to the reactor in a semi-batch manneraccording to Table 1.

TABLE 1 Reaction Time (hr) Urea mass (g) Urea percentage (%) 0 12.40 30%2 4.13 10% 4 4.13 10% 6 4.13 10% 8 4.13 10% 10 4.13 10% 12 4.13 10% 154.13 10%

The total reaction time was 18 hours. After the reaction was complete,the heating mantle was shut down and the agitation rate was reduced to60 rpm. When the reactor temperature dropped to 60° C., thepolycarbamate product was poured out from the reactor. The final productwas analyzed using ¹³C NMR. The hydroxyl conversion of the final productwas 72.0%. The byproduct levels are summarized in Table 2.

TABLE 2 Biuret + Cyanuric acid + Biuret (wt % in Cyanuric AcidPolyallophanate polyallophate 100% solids (wt % in 100% (wt % in 100%(wt % in 100% product) solids product) solids product) solids product)0.86% 0.00% 1.13% 1.99%The final polycarbamate product color was Gardner level-3.

Inventive Example 2: Semi-Batch Addition of Urea to Polyol in thePresence of Zinc Acetylacetonate

A 1-L reactor with heating mantle was used in the reaction. The reactorwas equipped with an agitator, a thermal-couple and a nitrogen sparger.A water-cooled condenser was connected to the adaptor on the reactorlid. The overhead condensate was collected by a receiver and thenon-condensable went through a bubbler filled with mineral oil and thenentered a 1-L scrubber filled with water.

785.93 g PARALOID AU-608X polyol which consists of 58% solid and 42%solvent (xylenes) was added to the reactor, which had 0.70 mol hydroxylfunctionality. 5.04 g zinc acetylacetonate (99% pure) was added to thereactor. The heating mantle was started and set at 158° C. The nitrogensparging flow rate was set at 20 sccm. The reaction mixture was agitatedat 100 rpm and then adjusted to 400 rpm when the reactor temperature wasover 60° C. 42.41 g 99% pure urea was dissolved in 39.31 g deionizedwater to form aqueous solution. When the reactor temperature reached138° C., the urea aqueous solution was fed into the reactor using asyringe pump and the reaction timer was started. The aqueous ureasolution was fed at 2 ml/min for 10 minutes and then decreased to 5ml/hr. The total feeding time was about 10 hours. Once the feeding ofurea was done, the reaction continued until the total reaction timereached 20 hours. The reaction was carried out between 138-142° C. Afterthe reaction was complete, the heating mantle was shut down and theagitation rate was reduced to 60 rpm. When the reactor temperaturedropped to 60° C., the polycarbamate product was poured out from thereactor. The final product was analyzed using ¹³C NMR. The hydroxylconversion of the final product was 48.1%. The byproduct levels aresummarized in Table 3.

TABLE 3 Biuret + Cyanuric acid + Biuret (wt % in Cyanuric AcidPolyallophanate polyallophate 100% solids (wt % in 100% (wt % in 100%(wt % in 100% product) solids product) solids product) solids product)0.38% 0.00% 0.62% 1.00%The final polycarbamate product color was Gardner level 3.

Inventive Example 3: Semi-Batch Addition of Urea to Polyol in Presenceof Zn 2-Ethylhexanoate

A 1-L reactor with heating mantle was used in the reaction. The reactorwas equipped with an agitator, a thermal-couple and a nitrogen sparger.A water-cooled condenser was connected to the adaptor on the reactorlid. The overhead condensate was collected by a receiver and thenon-condensable went through a bubbler filled with mineral oil and thenentered a 1-L scrubber filled with water.

827.67 g PARALOID AU-608X polyol which consists of 58% solid and 42%solvent (xylenes) was added to the reactor, which had 0.74 mol hydroxylfunctionality. 7.02 g zinc 2-ethylhexanoate (which has 22% zinc, 1%diethylene glycol monomethyl ether) was added to the reactor. 37.97 gurea (99% pure) was used in this reaction. The heating mantle wasstarted and set at 158° C. The nitrogen sparging flow rate was set at 20sccm. The reaction mixture was agitated at 100 rpm and then adjusted to400 rpm when the reactor temperature was over 60° C. 47.1% of Urea(17.87 g) was added to the reactor when the reactor temperature reached138° C. and the reaction timer was started. The reaction was carried outbetween 138-142° C. When the reaction time reached 4 hours, 29.4% urea(11.17 g) was added to the reactor. When the reaction time reached 7hours, the rest 23.5% urea (8.93 g) was added to the reactor. The totalreaction time was 12 hours. The reaction was carried out between138-142° C. After the reaction was complete, the heating mantle was shutdown and the agitation rate was reduced to 60 rpm. When the reactortemperature dropped to 60° C., the polycarbamate product was poured outfrom the reactor. The final product was analyzed using ¹³C NMR. Thehydroxyl conversion of the final product was 52.6%. The byproduct levelsare summarized in Table 4.

TABLE 4 Biuret + Cyanuric acid + Biuret (wt % in Cyanuric AcidPolyallophanate polyallophate 100% solids (wt % in 100% (wt % in 100%(wt % in 100% product) solids product) solids product) solids product)0.73% 0.00% 0.48% 1.21%The final polycarbamate product color was Gardner level-3.

Inventive Example 4: Semi-Batch Addition of Urea to Polyol in Presenceof Zn 2-Ethylhexanoate

A 1-L reactor with heating mantle was used in the reaction. The reactorwas equipped with an agitator, a thermal-couple and a nitrogen sparger.A water-cooled condenser was connected to the adaptor on the reactorlid. The overhead condensate was collected by a receiver and thenon-condensable went through a bubbler filled with mineral oil and thenentered a 1-L scrubber filled with water.

933.41 g PARALOID AU-608X polyol which consists of 58% solid and 42%solvent (xylenes) was added to the reactor, which had 0.83 mol hydroxylfunctionality. 7.91 g zinc 2-ethylhexanoate (which has 22% zinc, 1%diethylene glycol monomethyl ether) was added to the reactor. Theheating mantle was started and set at 158° C. The nitrogen sparging flowrate was set at 20 sccm. The reaction mixture was agitated at 100 rpmand then adjusted to 400 rpm when the reactor temperature was over 60°C. 44.33 g 99% pure urea was dissolved in 41.08 g deionized water toform aqueous solution. When the reactor temperature reached 138° C., theurea aqueous solution was fed into the reactor using a syringe pump andthe reaction timer was started. The aqueous urea solution was fed at 2ml/min for 10 minutes and then decreased to 5 ml/hr. The total feedingtime was about 10 hours. Once the feeding of urea was done, the reactioncontinued until the total reaction time reached 15 hours. The reactionwas carried out between 138-142° C. After the reaction was complete, theheating mantle was shut down and the agitation rate was reduced to 60rpm. When the reactor temperature dropped to 60° C., the polycarbamateproduct was poured out from the reactor. The final product was analyzedusing ¹³C NMR. The hydroxyl conversion of the final product was 59.9%.The byproduct levels are summarized in Table 5.

TABLE 5 Biuret + Cyanuric acid + Biuret (wt % in Cyanuric AcidPolyallophanate polyallophate 100% solids (wt % in 100% (wt % in 100%(wt % in 100% product) solids product) solids product) solids product)0.14% 0.00% 0.59% 0.73%The final polycarbamate product color was Gardner level-2.

Inventive Example 5: Semi-Batch Addition of Urea to Polyol in thePresence of Zn 2-Ethylhexanoate

A 1-L reactor with heating mantle was used in the reaction. The reactorwas equipped with an agitator, a thermal-couple and a nitrogen sparger.A water-cooled condenser was connected to the adaptor on the reactorlid. The overhead condensate was collected by a receiver and thenon-condensable went through a bubbler filled with mineral oil and thenentered a 1-L scrubber filled with water. An Auger funnel was installedon the top of the reactor, which was driven by a motor to add urea solidto the reactor.

846.25 g PARALOID AU-608X polyol which consists of 58% solid and 42%solvent (xylenes) was added to the reactor, which had 0.75 mol hydroxylfunctionality. 8.74 g zinc 2-ethylhexanoate (which has 22% zinc, 1%diethylene glycol monomethyl ether) was added to the reactor. 40.19 gurea (99% pure) was used in this reaction. The heating mantle wasstarted and set at 158° C. The nitrogen sparging flow rate was set at 20sccm. The reaction mixture was agitated at 100 rpm and then adjusted to400 rpm when the reactor temperature was over 60° C.

When the reactor temperature reached 138° C., 34.1% urea (13.70 g) wasadded to the Auger funnel and the motor was started to slowly add ureasolid to the reactor. The reaction timer was started. It took about 9minutes 30 seconds to load the urea into the reactor. The Auger funnelmotor was shut down. When the reaction time reached 4 hours, 28.4% urea(11.42 g) was added to the Auger funnel and the motor was started. Ittook about 7 minutes 40 seconds to load the urea into the reactor andthe motor was shut down. When the reaction time reached 7 hours, 22.7%(9.13 g) urea was loaded into the Auger funnel and the motor wasstarted. It took about 6 minutes 25 seconds to load the urea into thereactor. When the reaction time reached 10 hours, the rest 14.8% urea(5.94 g) was loaded into the Auger funnel and the motor was started. Ittook about 4 minutes 15 seconds to load the urea to the reactor.

The reaction was carried out until the total reaction time reached 20hours. The reaction was carried out between 138-142° C. After thereaction was complete, the heating mantle was shut down and theagitation rate was reduced to 60 rpm. When the reactor temperaturedropped to 60° C., the polycarbamate product was poured out from thereactor. The final product was analyzed using ¹³C NMR. The hydroxylconversion of the final product was 75.4%. The byproduct levels aresummarized in Table 6.

TABLE 6 Biuret + Cyanuric acid + Biuret (wt % in Cyanuric AcidPolyallophanate polyallophate 100% solids (wt % in 100% (wt % in 100%(wt % in 100% product) solids product) solids product) solids product)0.50% 0.00% 1.52% 2.01%The final polycarbamate product color was Gardner level-3.

Comparative Example 1: Batch Reaction of Methyl Carbamate with Polyol inPresence of Zinc Acetylacetonate

A 1-L reactor with heating mantle was used in the reaction. The reactorwas equipped with an agitator, a thermal-couple and a nitrogen sparger.A heated condenser was connected to the adaptor on the reactor lid. Aheating batch equipped with a circulation pump was used to heat watercirculating in the condenser. The overhead condensate was collected by areceiver and the non-condensable went through a bubbler filled withmineral oil and then entered a 1-L scrubber filled with water.

750.22 g PARALOID AU-608X polyol which consists of 58% solid and 42%solvent (xylenes) was added to the reactor, which had 0.67 mol hydroxylfunctionality. 4.81 g zinc acetylacetonate (99% pure) was added to thereactor. The heating mantle was started and set at 158° C. The heatingbatch for the overhead condenser was set at 70° C. The nitrogen spargingflow rate was set at 20 sccm. The reaction mixture was agitated at 100rpm and then adjusted to 400 rpm when the reactor temperature was over60° C. When the reactor temperature reached 70° C., 51.12 g (98% pure)methyl carbamate was added to the reactor. When the reactor temperaturereached 138° C., the reaction timer was started.

The total reaction time was 20 hours. The reaction was carried outbetween 138-142° C. After the reaction was complete, the heating mantlewas shut down and the agitation rate was reduced to 60 rpm. When thereactor temperature dropped to 60° C., the polycarbamate product waspoured out from the reactor. The final product was analyzed using ¹³CNMR. The hydroxyl conversion of the final product was 71.9%.

Inventive Example 6: Semi-Batch Addition of Urea to Polyol in thePresence of Manganese(II) Acetylacetonate

A 1-L reactor with heating mantle was used in the reaction. The reactorwas equipped with an agitator, a thermal-couple and a nitrogen sparger.A water-cooled condenser was connected to the adaptor on the reactorlid. The overhead condensate was collected by a receiver and thenon-condensable went through a bubbler filled with mineral oil and thenentered a 1-L scrubber filled with water.

771.04 g PARALOID AU-608X polyol which consists of 58% solid and 42%solvent (xylenes) was added to the reactor, which had 0.69 mol hydroxylfunctionality. 4.75 g Manganese(II) Acetylacetonate (99% pure) was addedto the reactor. The heating mantle was started and set at 158° C. Thenitrogen sparging flow rate was set at 20 sccm. The reaction mixture wasagitated at 100 rpm and then adjusted to 400 rpm when the reactortemperature was over 60° C. 41.61 g urea (99% pure) was used in thereaction. The urea solid was added to the reactor in a semi-batchmanner. When the reactor temperature reached 138° C., 30% of the totalurea (12.48 g) was added to the reactor. The reaction timer was alsostarted. The urea additions are shown in Table 7.

TABLE 7 Reaction time (hour) Urea Mass (g) Urea Percentage (%) 0 12.4830% 2 4.16 10% 4 4.16 10% 6 4.16 10% 8 4.16 10% 10 4.16 10% 12 4.16 10%15 4.16 10%

The total reaction time was 18 hours. The reaction was carried outbetween 138-142° C. After the reaction was complete, the heating mantlewas shut down and the agitation rate was reduced to 60 rpm. When thereactor temperature dropped to 60° C., the polycarbamate product waspoured out from the reactor. The final product was analyzed using ¹³CNMR. The hydroxyl conversion of the final product was 68.2%. Thebyproduct levels are summarized in Table 8.

TABLE 8 Biuret + Cyanuric acid + Biuret (wt % in Cyanuric AcidPolyallophanate polyallophate 100% solids (wt % in 100% (wt % in 100%(wt % in 100% product) solids product) solids product) solids product)0.11% 0.00% 0.61% 0.73%The final polycarbamate product color was Gardner level-3.

High Throughput Inventive Examples

Carbamylation reactions of an acrylic polyol (AU608x) using both methylcarbamate and urea were carried out in an array of 48 high throughputreactors with an internal volume of 35 mL (utilizing glass tubeinserts), equipped with stirring and capable of continuous nitrogenpurge of the reactor head space to remove the volatile by products(ammonia gas).

A comprehensive list of compounds based on different metals and ligandswas tested in this study. Experiments were carried out in sets of 48 intriplicates. Each set of 48 contained four experiments using dibutyltinoxide and two experiments with no catalyst, as control experiments.Pre-weighed glass tubes were loaded with about 9 g of a 65% solution ofAu608x polyol in xylene. They were then weighed to determine the exactweight of polyol added. Urea and catalyst were then added based on theweight of the polyol in order to achieve a molar (urea/OH) ratio of 0.6and hydroxyl groups and 1 wt % of catalyst, based on the weight ofpolyol; respectively. The tubes were then placed into the bottom part ofthe high throughput reactor. The reactor head was placed on top andclamped in order to seal the reactor. The reactor was then heated to140° C. while being purged by nitrogen.

FT-IR was used to monitor the disappearance of hydroxyl group as ameasure of the extent of each reaction. The experiments that wereconducted with dibutyltin oxide, Bu₂SnO, in each set of 48 were used asreference for comparing the efficiency of the each compound incatalyzing the carbamylation reaction, within that set. The extent ofreaction in each tube, as determined by FT-IR, was divided by theaverage of the extent of reaction utilizing Bu₂SnO in that set. This wasto block the potential set-to-set variability in the experiments thatmight have existed.

Relative conversion data for the carbamylation experiments, includingthe results of the “no catalyst” reactions, are shown in Table 9.

TABLE 9 Catalyst Relative Conversion calcium tri-fluoromethanesulfonate0.79 zinc trifluoro acetate hydrate 0.92 zinc(II) acetylacetonatehydrate 1.01 Calcium acetylacetonate 0.90Bis(2,2,6,6-tetramethyl-3,5-hetanedionato) 0.89 zinc(II) zinc(II)dibutyldithiocarbamate 0.91 Calcium Stearate 0.88 Magnesiumacetylacetonate 0.97 Magnesium Stearate 1.00 2-Mercaptopyridine N-OxideZinc Salt 0.79 Magnesium trimethane sulfonate 0.83 Zinchexafluoroacetylacetonate hydrate 0.90 Zinc (II) Dibutyldithiocarbamate0.94 Toluenesulfonic acid zinc salt hydrate 1.00 Zinc trifluoroacetatehydrate 0.95 Bu2SnO 1.01 Bu2SnO 1.01 Bu2SnO 0.99 Bu2SnO 0.99 No catalyst0.59 No catalyst 0.54

Test Methods

OH Number Titration

Where OH number is the magnitude of the hydroxyl number for a polyol asexpressed in terms of milligrams potassium hydroxide per gram of polyol(mg KOH/g polyol). Hydroxyl number (OH #) indicates the concentration ofhydroxyl moieties in a composition of polymers, particularly polyols.The hydroxyl number for a sample of polymers is determined by firsttitrating for the acid groups to obtain an acid number (mg KOH/g polyol)and secondly, acetylation with pyridine and acetic anhydride in whichthe result is obtained as a difference between two titrations withpotassium hydroxide solution, one titration with a blank for referenceand one titration with the sample. A hydroxyl number is the weight ofpotassium hydroxide in milligrams that will neutralize the aceticanhydride capable of combining by acetylation with one gram of a polyolplus the acid number from the acid titration in terms of the weight ofpotassium hydroxide in milligrams that will neutralize the acid groupsin the polyol. A higher hydroxyl number indicates a higher concentrationof hydroxyl moieties within a composition. A description of how todetermine a hydroxyl number for a composition is well-known in the art,for example in Woods, G., The ICI Polyurethanes Book, 2^(nd) ed. (ICIPolyurethanes, Netherlands, 1990).

Gardner color: was measured according to ASTM D1544 “Standard TestMethod for Color of Transparent Liquids (Gardner Color Scale)” using aHunterLab colorimeter.

¹³C NMR: All samples were characterized by ¹³C NMR in solutions. For atypical sample preparation, 0.6 g dry material was dissolved in 2.5 mLDMSO-d₆ solvent at room temperature in a glass vial. The DMSO-d₆ solventcontains 0.015 M Cr(acac)₃ as a relaxation agent. The solution was thentransferred to a 10 mm NMR tube for characterization. Quantitativeinverse-gated ¹³C NMR experiments were performed on a Bruker Avance 400MHz (¹H frequency) NMR spectrometer equipped with a 10 mm DUAL C/Hcryoprobe. All experiments were carried out without sample spinning at25.0° C. Calibrated 90° pulse was applied in the inverse-gated pulsesequence. The relaxation delay between consecutive data acquisitions is5*T₁, where T₁ is the longest spin-lattice relaxation time of all nucleiin the measured system. The ¹³C NMR spectra were processed with a linebroadening of 1 Hz, and referenced to 39.5 ppm for the DMSO-d₆ resonancepeak.

Information that can be obtained from ¹³C NMR spectra includes thepercent of hydroxyl conversion, byproduct levels and solid content ofthe reaction product. The carbon next to a hydroxyl group has a chemicalshift change after the carbamylation reaction. The hydroxyl conversionwas calculated from the peak intensity ratio of the carbon after andbefore a carbamylation reaction. In a quantitative ¹³C NMR spectrum,each component of the measured system has a unique resonance peak, andits peak intensity is proportional to the molar concentration of thatspecies. The byproduct levels and solid content were calculated byintegrating the desired peaks. The molar concentration can be convertedto weight percentage if the molecular weights for all species are known.In calculating the solid content, any components other than knownsolvents are classified as solid.

The present invention may be embodied in other forms without departingfrom the spirit and the essential attributes thereof, and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicating the scope of the invention.

We claim:
 1. A process to prepare polycarbamate comprising: adding ureato a polyol in the presence of at least one catalyst selected from thegroup consisting of Zn 2-ethylhexanoate, Zn acetylacetonate, Mn(II)acetylacetonate wherein the process exhibits equal to or greater than45% hydroxyl conversion at a reaction time from 10 to 25 hours and areaction temperature from 130 to 145° C.; recovering a solid productcomprising polycarbamate and less than 2 wt % polyallophanate based on atotal weight of the solid product.
 2. The process according to claim 1,wherein a second catalyst selected from the group consisting ofcarbamylation catalysts is present.
 3. The process according to claim 2,wherein the second catalyst is dibutyltin oxide and/or dibutyltinacetate.